The air pollution problems associated with such combustion by-products as, for example, the various oxides of nitrogen, sulfur, carbon, phosphorus, mercury and other metals, the various halides such as HCl and HBr, the phosphoryl compounds, the many other volatile metal halides, oxides and complexes, the various sulfur containing compounds such as hydrogen sulfide or carbon disulfide, and the organic toxic pollutants such as dioxin and the like which are in themselves highly volatile and elusive, or are strongly adsorbed on fly ash, are well recognized and of course, are the subject of intensive international research and development effort. Such by-products typically are produced through garbage or trash incineration, or building heating, power production or the like from fossil or other fuels.
Industry has responded to these problems with many pollution control devices and processes such as off-gas scrubbing, filtering, electrical precipitation, electric are afterburning, catalytic burning, baffled flues and chimneys, and the like, many of which are of limited practical valve, particularly for the effective removal of many of the above by-products, fly ash and other particulate fines, and practically all of which devices require large and expensive special auxilliary off-gas handling equipment and housing structures therefor. Ofttimes these control devices are not adaptable to existing flue equipment and the cooperating or supporting equipment or installations comprises several buildings or at least several interconnected but separate installations of scrubbers, cyclone separators, filter equipment, economizers, and the like, which necessarily complicate the off-gas treatment aspect, from both the labor and apparatus standpoint, particularly maintenance, and leads to unmanageable cost of off-gas clean up. Typical such prior installations are depicted and discussed in the Allen Hershkowitz article in Technology Review, Jul. 30, 1987, and in U.S. Pat. Nos. 3,710,555; 3,706,182; 3,695,004; 3,984,220; 4,095,514; 4,286,973; 4,206,722; 4,635,569; and 3,442,232, the disclosures of all of which are incorporated herein by reference, particularly the relevant structures thereof, e.g., the spray or jet nozzles.
Objects of the present invention therefore, are:
(1) to provide a treatment process and apparatus for decontaminating the air (off-gas) of combustion systems, which process and apparatus are useable as original process and equipment of, or readily adaptable to, existing combustion units comprised of fire box and flue structures, at minimum reconstruction effort and cost, and which are highly effective in essentially eliminating combustion produced air contaminants of all types which are carried in the off-gas. As a result, substantial amounts of the contaminant diminished air can be recycled to the combustion unit or sent to other substantially contained equipment for use in various chemical or other industrial processes such that actual off-gas emissions to the atmosphere are essentially eliminated; PA1 (2) to provide such process and apparatus which provide chemical treatment means for the off-gas, adaptable to automatic, electronic and computerized control; PA1 (3) to provide such process and apparatus with continuous or semi-continuous off-gas monitoring analysis, computer interpretation of the analysis data, and computer regulation of chemical reactor means within the flue system for reacting out normally pollutant contaminant chemicals in response to said computer interpretation; PA1 (4) to provide such method and apparatus in a substantially closed-loop form to thereby essentially eliminate atmospheric contamination; and PA1 (5) to provide such method and apparatus which are energy efficient and capable of effectively generating power, particularly electric power, and also capable of feeding various industrial gas processing installations such as dry ice manufacture, sulfuric acid manufacture, and oxo processes. PA1 (a) analyzing the chemical composition of the off-gas at one or more locations in said flue system; PA1 (b) directing the off-gas from the fire box means into chemical treatment chamber means dynamically maintained within a predesigned off-gas pressure range; PA1 (c) contacting the off-gas in said treatment chamber means with reactant chemical means previously adjusted in reactivity and specificity according to the chemical analysis of the off-gas, for converting prescribed amounts of one or more of said contaminants in said off-gas to one or more desired decontamination products; PA1 (d) exiting the treated off-gas from said treatment chamber means to expansion chamber means maintained within a dynamically predesigned off-gas pressure range lower than pressures maintained in said treatment chamber means to effect a reduction in the kinetic energy of the treated off-gas and thus facilitate removal of said products therefrom; and PA1 (e) removing a desired amount of said products from the off-gas. PA1 (1) the reduced kinetic energy off-gas is passed through filtering means for removing particulate matter therefrom prior to exiting to said gas processing means; PA1 (2) said off-gas in said expansion chamber means is scrubbed with aqueous material to separate particulate matter therefrom; PA1 (3) the temperature and kinetic energy of the off-gas in the flue system is further reduced by contact of the off-gas with heat exchanger cooling means; PA1 (4) said reactant chemical means comprises aqueous material containing at least one reactant chemical and is injected as a spray into said off-gas; PA1 (5) the off-gas from the expansion chamber means is directed to gas separation means for separating exiting carry-over gases comprising one or more of carbon monoxide, carbon dioxide, nitrogen containing gases, sulfur containing gases, oxygen, hydrogen and water vapor, and selectively feeding one or more industrial gas processing installations specific to each gas for the conversion therein to non-pollutant product; PA1 (6) the separated carbon dioxide is fed to dry ice manufacturing means, and/or the separated carbon nonoxide is fed to hydroformylation reactor means; PA1 (7) the off-gas from the expansion chamber means is directed to power generating turbine means; PA1 (8) a portion of said off-gas from said expansion chamber means is recycled to the combustion system; PA1 (9) plural pairs of treatment chamber means and expansion chamber means are employed in a series arrangement in concert with reactant chemical selection to reduce to a minimum the pollutant type contaminants present in the off-gas; and PA1 (10) the products-diminished off-gas is directed to substantially contained gas processing means substantially isolated from the atmosphere. PA1 (a) chemical treatment chamber means defined by PA1 (b) reactor means communicating with said treatment chamber means and adapted to provide reactant chemicals thereto for contact with the off-gas in said treatment chamber means for producing decontamination product; PA1 (c) reactant chemical selecting means associated with said reactor means and adapted for providing selected chemicals and concentrations thereof to said reactor means; PA1 (d) control means communicating with the off-gas at one or more locations within said system for qualitatively and quantitatively analyzing the same and actuating said selecting means in relationship to said analysis to provide selected reactant chemicals in predetermined quantities to said reactor means for contact with said off-gas to selectively control the types and concentrations of said matter therein; PA1 (e) second wall means defining expansion chamber means communicating with said outlet means of said treatment chamber means and adapted to provide a reduced pressure region of treated off-gas received from said treatment chamber means; PA1 (f) exhaust port means in said second wall means for exiting the treated, reduced kinetic energy off-gas from said expansion chamber means; and PA1 (g) cooling means for the off-gas in one or more selected portions of said system. PA1 (1) at least one combination of interconnected chemical treatment chamber means and expansion chamber means is stacked on top of the first combination thereof and communicates with said exhaust port means of the first expansion chamber means to provide repetitive off-gas purification; PA1 (2) said treatment chamber means is elongated and adapted for positioning above and in communication with the fire box of a combustion unit with its longitudinal axis oriented substantially vertically; PA1 (3) said control means provides substantially continuous off-gas analysis and reactant chemical selection; PA1 (4) said reactor means comprises multiple fluid streams of different reactant chemical compositions; PA1 (5) cooling means is provided for maintaining said expansion chamber means at a reduced temperature; PA1 (6) said expansion chamber means is positioned substantially vertically above said treatment chamber means; PA1 (7) common cooling means is provided for said reactor means and second chamber means; PA1 (8) said common cooling means comprises heat exchanger means within said expansion chamber means or proximate thereto; PA1 (9) the outlet means of said treatment chamber means provides expansion orifice means communicating with said expansion chamber means; and PA1 (10) gas processing means is provided communicating with said exhaust port means for receiving the treated off-gas from said expansion chamber means and is adapted to convert said treated off-gas to non-pollutant products or uses.